Catalysts for the metathesis of olefins and functionalized olefins

ABSTRACT

A catalyst for the metathesis of olefins and functionalized olefins, which contains a compound having the formula B 2  O 3  -Re 2  O 7  /Al 2  O 3  -SiO 2 .

This is a division of application Ser. No. 07/658,861, filed on Feb. 22,1991, now U.S. Pat. No. 5,143,885.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to heterogeneous catalysts on an Al₂ O₃--SiO₂ substrate for the metathesis of olefins and functionalizedolefins.

2. Description of the Background

The metathesis of olefinic hydrocarbons is employed in the manufactureof specific olefins, dienes and polyenes and unsaturated polymers. Evenolefins with functional groups are subject to the metathesis reaction,provided suitable catalysts are used. Of special importance is themetathesis of unsaturated fatty acid methyl esters, which are producedon large scale by transesterifying native fats and oils with methanoland are, thus, commercially available as parent compounds. Themetathesis of these esters opens new simple access to intermediateproducts that are important from a chemical engineering point of viewfor the industrial production of surfactants, plastics, plasticizers,lubricants and a whole range of fine chemicals.

According to Bosma et al., Journal of Organometallic Chemistry, vol. 255(1983), pp. 159-171, the metathesis of unsaturated esters can beperformed on a Re₂ O₇ /Al₂ O₃ catalyst, which is activated with anorgano-tin compound of the general formula SnR₄. To manufacture thecatalyst, γ-Al₂ O₃ is impregnated with ammonium perrhenate.

Warwel, Erdol-Erdgas-Kohle, Petroleum, Natural Gas, Coal, vol. 103(1987), pp. 238-45, describes industrial metathesis procedures, whereinpredominantly Re₂ O₇ /Al₂ O₃ --, CoO-MoO₃ /Al₂ O₃ and WO₃ /SiO₂catalysts are used. Accordingly, only the Re₂ O₇ /Al₂ O₃ catalyst isalready active at room temperature.

According to FR 2 521 872, the metathesis of functionalized olefins canbe performed on Re₂ O₇ /Al₂ O₃ --SiO₂ catalysts. The substrate containspreferably only 10 to 30% SiO₂. According to this process, organic leadcompounds of the formula PbR₄ are used as activators.

In NL-A-84 03 051 the metathesis is preferably performed on SiO₂ -richsupported catalysts. The Re₂ O₇ /Al₂ O₃ --SiO₂ catalysts contain in thesubstrate preferably 65 to 90% SiO₂. The activators used are preferablytin tetraethyl and tin tetrabutyl.

Unfortunately, in order to use catalysts effectively in metathesisreactions, it is, at present, necessary to use high concentrations orlarge amounts of catalysts. This is particularly true in the metathesisof unsaturated esters. In fact, there are no catalysts which are, atpresent, commercially feasible in the metathesis of unsaturated fattyacid esters.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a moreeffective catalyst for the metathesis of olefins and functionalizedolefins.

It is also a particular object of this invention to provide a moreeffective catalyst for the metathesis of unsaturated fatty acid estersto provide higher conversions and higher yields.

The above objects and others which will become more apparent in view ofthe following disclosure are provided by a catalyst for the metathesisof olefins and functionalized olefins, which comprises a compound havingthe composition B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, catalysts are providedcontaining a compound having the formula B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂.In these catalysts boron oxide and rhenium oxide are the compounds thatact as the actual catalyst.

The aluminosilicate Al₂ O₃ --SiO₂ is the carrier. Surprisingly, it hasbeen found that the catalyst action on an aluminosilicate carrier ishigher than on either a SiO₂ or an Al₂ O₃ carrier alone. In the carrier,the SiO₂ content ranges preferably from 20 to 50 percent by weight,however, a content ranging from 35 to 50 percent by weight is especiallypreferred.

The B₂ O₃ --Re₂ O₇ content ranges from 2 to 30 percent by weight. At thesame time, the B₂ O₃ content can range from 1 to 20 percent by weight.The content ranges preferably from 2 to 10 percent by weight. The Re₂ O₇content fluctuates in the range of 1 to 20 percent by weight. Two to 15percent by weight of Re₂ O₇ are preferred. The percents by weight arebased on the aluminosilicate carrier.

To manufacture the present catalysts, the Al₂ O₃ --SiO₂ carrier isimpregnated with a salt or another compound of the catalytically activeelements. Thus, the carrier can be simultaneously impregnated with boricacid and ammonium perrhenate. After drying and heating, the oxidiccatalyst is produced. However, one can also apply in succession firstboric acid, then dewatering and transfer into the oxide and thenimpregnation with the rhenium salt, drying the rhenium salt and alsotransfer into the oxide.

The catalysts of the invention can be added as a powder, granulate or asa honeycomb. The catalysts are used preferably as a powder.

The B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂ catalysts are significantly moreeffective for metathetical reactions than known catalysts, which containno B₂ O₃ or, instead of an Al₂ O₃ --SiO₂ carrier, utilize a γ-Al₂ O₃carrier.

When olefin hydrocarbons are metathesized, no activator is required inaddition to the catalysts of the invention. During the metathesis offunctionalized olefins or during the co-metathesis of olefins andfunctionalized olefins the addition of an activator is, however,required.

Functionalized olefins, as specified by the invention, are unsaturatedesters, esters, halogen and nitrogen compounds, aldehydes, ketones, andderived alcohols and derived carboxylic acids. Preferably, unsaturatedcarboxylates are added.

Suitable activators are organo-tin compounds, where tin tetraalkyl ofthe formula SnR₄ is preferred, where R is alkyl having 1 to 8 carbonatoms. Examples for R are methyl, ethyl, isopropyl and n-butyl.

Preferably, the activator is added in such quantities that the molarratio of Re₂ O₇ :SnR₄ ranges from 5:1 to 1:5. In particular, a molarratio ranging from 2:1 to 1:2 is preferred.

With the combination of B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂ catalyst and SnR₄activator, both pure olefin hydrocarbons and functionalized olefins,e.g., unsaturated carboxylic acid esters, can be metathesized, whereinin the latter case even at a molar ratio of Re₂ O₇ :ester of 1:1,000high conversions can still be obtained. The metathetical reactions canbe performed as homo-metathesis, as co-metathesis (use of two differentolefinic compounds) and in the case of cycloolefins as the substrate asmetathetical, ring-opening polymerization. The metathetical reactionsare carried out preferably at room temperature, a state that isadvantageous for reasons relating to energy conservation. However, theuse of a lower or higher temperature is also possible.

The present invention will now be illustrated by reference to certainExamples which are provided for purposes of illustration and are notintended to be limitative.

EXAMPLE 1 Preparation of the Catalyst B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂

In a 250 ml single neck flask, 0.55 g of NH₄ ReO₄ and 1.17 g of H₃ BO₃are dissolved in 135 ml of dioxan and 15 ml of H₂ O. Following theaddition of 10 g previously at 500° C. in an air current of calcinatedaluminosilicate with 40 percent by weight of SiO₂, the entire mixture isheated at reflux overnight. Subsequently, the solvent is removed bydistillation and the solid is predried in a water jet vacuum at 130° C.The predried contact is heated to 500° C. in the air current and left atthis temperature for 16 hours. Then, it is cooled to room temperatureunder argon. A Re₂ O₇ content of 4.4 percent by weight and B₂ O₃ contentof 5.8 percent by weight is found by elementary analysis.

EXAMPLE 2 Co-metathesis of 10-undecenoic Acid Methyl Ester With 4-octeneCatalyst: B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂ +Sn(n--C₄ H₉)₄

In a preheated 50 ml shaker flask filled with argon and comprisingmagnetic stirring cores, 0.5 g of the catalyst (with 0.045 mmol Re₂ O₇)prepared in Example 1 are introduced and treated with 0.57 g (0.54 ml)of a SnBu₄ solution (0.1 molar in chlorobenzene, with 0.054 mmol SnBu₄)and 1 ml of chlorobenzene. Then 8.06 g (11.23 ml) of 4-octene (72 mmol)and 7.13 g (8.03 ml) of 10-undecenoic acid methyl ester (36 mmol) areadded, where the molar ratio of the individual components is as follows:

    Re.sub.2 O.sub.7 :SnBu.sub.4 :C.sub.11 -ester:4-octene=1:1.2:800:1,600

After stirring for 2 hours at room temperature, a sample is taken with asyringe and analyzed gas chromatographically following the addition of afew drops of methanol to decompose any catalyst residues.

According to the reaction equation: ##STR1## the reaction mixturecontains, in addition to the parent compounds, 1-pentene and10-tetradecenoic acid ester. Through homo-metathesis of 10-undecenoicacid ester, a small amount of unsaturated C₂₀ -diester is also formed inaccordance with the reaction: ##STR2##

The conversion of the added 10-undecenoic acid ester amounts to 77%. Ofthe regenerated esters, the C₁₄ -monoester constitutes 87 percent byweight and the C₂₀ -diester constitutes 13 percent by weight.

COMPARISON EXAMPLE A Co-metathesis of 10-undecenoic Acid Methyl EsterWith 4-octene Catalyst: Re₂ O₇ /Al₂ O₃ --SiO₂ +Sn(n--C₄ H₉)₄

The experiment from Example 2 is repeated; however, a B₂ O₃ -freecatalyst is added. Compared to Example 2, the reaction conversion dropsto 59%.

COMPARISON EXAMPLE B Co-metathesis of 10-undecenoic Acid Methyl EsterWith 4-octene Catalyst: B₂ O₃ --Re₂ O₇ /gama--Al₂ O₃ +Sn(n--C₄ H₉)₄

The experiment from Example 2 is repeated; however, a SiO₂ -freecatalyst is added (exchange of aluminosilicate for γ-Al₂ O₃). Comparedto Example 2, the reaction conversion drops to 30%.

EXAMPLE 3 Co-metathesis of Oleic Acid Methyl Ester With 4-octeneCatalyst: B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂ +Sn(n--C₄ H₉)₄

In a preheated 50 ml shaker flask filled with argon and comprisingmagnetic stirring cores, 0.5 g of the catalyst (with 0.045 mmol Re₂ O₇)prepared in Example 1 are introduced and treated with 0.57 g (0.54 ml)of a SnBu₄ solution (0.1 molar in chlorobenzene, with 0.054 mmol SnBu₄)and 1 ml of chlorobenzene. Then 8.06 g of 4-octene (72 mmol) and 10.63 gof oleic acid methyl ester (36 mmol) are added, where the molar ratio ofthe individual components is as follows:

    Re.sub.2 O.sub.7 :SnBu.sub.4 :oleic acid methyl ester:4-octene=1:1.2:800:1,600.

After a reaction period of 2 hours at room temperature, a sample istaken and analyzed gas chromatographically following the addition of afew drops of methanol to decompose any catalyst residues.

According to the reaction equation: ##STR3## the reaction mixture nowcontains 4-tridecene and 9-tridecenoic acid ester. Throughhomo-metathesis of the oleic acid methyl ester according to thereaction: ##STR4## small amounts of 9-octadecene and 9-octadecenoicdiacid dimethyl ester are also formed.

A reaction conversion of the added oleic acid methyl ester of 81% isfound. The regenerated esters comprise 89 percent by weight of theunsaturated C₁₃ -monoester and 11 percent by weight cf the unsaturatedC₁₈ -diester.

COMPARISON EXAMPLE C Co-metathesis of Oleic Acid Methyl Ester With4-octene Catalyst: Re₂ O₇ /Al₂ O₃ --SiO₂ +Sn(n--C₄ H₉)₄

The experiment from Example 3 is repeated; however, a B₂ O₃ -freecatalyst is added. Now the conversion drops to 40%.

COMPARISON EXAMPLE D Co-metathesis of Oleic Acid Methyl Ester With4-octene Catalyst: B₂ O₃ --Re₂ O₇ /gama--Al₂ O₃ +Sn(n--C₄ H₉)₄

The experiment from Example 3 is repeated; however, a SiO₂ -freecatalyst is added. In addition, the concentration of catalyst andactivator is nearly doubled. Now the molar ratio for Re₂ O₇ :SnBu₄ oleicacid methyl ester:4-octene=1:1.5:500:1,000. Nevertheless, the conversiondrops to 27%.

EXAMPLE 4 Homo-metathesis of 10-undecenoic Acid Methyl Ester Catalyst:B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂ +Sn(n--C₄ H₉)₄

In a preheated 50 ml shaker flask filled with argon and comprising areflux condenser to which a bubble counter is attached, 0.5 g of thecatalyst prepared in Example 1 are introduced and treated with 0.57 g(0.54 ml) of a SnBu₄ solution (0.1 molar in chlorobenzene) and 1 ml ofchlorobenzene. Then 3.57 g 10-undecenoic acid methyl ester (18 mmol) areadded, where the molar ratio of the individual components is as follows:

    Re.sub.2 O.sub.7 :SnBu.sub.4 :C.sub.11 -ester=1:1.2:400

After 2 hours at room temperature, a conversion of 49% is determined bymeans of gas chromatography. When the experiment is repeated at 80° C.,a conversion of 60% is determined after 2 hours. In both experiments,according to ##STR5## in addition of ethylene, 10-eicosenoic diacidmethyl ester is formed exclusively.

EXAMPLE 5 Homo-metathesis of Oleic Acid Methyl Ester Catalyst: B₂ O₃--Re₂ O₇ /Al₂ O₃ --SiO₂ +Sn(n--C₄ H₉)₄

In a preheated 50 ml shaker flask filled with argon and comprisingmagnetic stirring cores, 0.5 g of the catalyst prepared in Example 1 areintroduced and treated with 0.57 g (0.54 ml) of a SnBu₄ solution (0.1molar in chlorobenzene) and 1 ml of chlorobenzene. Then 5.32 g of oleicacid methyl ester (18 mmol) are added, where the molar ratio of theindividual components is as follows:

    Re.sub.2 O.sub.7 :SnBu.sub.4 oleic acid methyl ester=1:1.2:400

After 2 hours at 80° C., a 45% conversion of the oleic acid methyl esterto 9-octadecene and 9-octadecenoic diacid dimethyl ester according tothe reaction: ##STR6## obtained.

EXAMPLE 6 Co-metathesis of 4-octene With 5-decene

Catalyst: B₂ O₃ --Re₂ O₇ /Al₂ O₃ --SiO₂ +Sn(n--C₄ H₉)₄

In a preheated 50 ml shaker flask filled with argon and comprisingmagnetic stirring cores, 1.6 g of the catalyst (with 0.146 mmol Re₂ O₇)prepared in Example 1 are introduced and treated with 1.7 ml of a 1molar SnBu₄ solution in chlorobenzene (with 0.173 mmol SnBu₄) and 1 mlof chlorobenzene. Then 13.1 g of 4-octene (116.8 mmol) and 16.4 g of5-decene (116.8 mmol) are added, where the molar ratio of the individualcomponents is as follows:

    Re.sub.2 O.sub.7 :SnBu.sub.4 :4-octene:5-decene=1:1.2:800:800.

After 2 hours at room temperature, a sample is taken and analyzed gaschromatographically. According to the reaction equation: ##STR7## thereaction mixture contains, in addition to the feedstocks, also 4-nonene.The conversion of the added olefin is 50%; the selectivity for 4-noneneis 98%.

EXAMPLE 7 Co-metathesis of 4-octene With 5-decene Catalyst: B₂ O₃ --Re₂O₇ /Al₂ O₃ --SiO₂

The experiment from Example 6 is repeated; however, no organo-tinactivator is used. In this experiment, too, a 50% conversion isdetermined by means of gas chromatography with a selectivity for4-nonene of 90%.

EXAMPLE 8 Homo-metathesis of 1-octene Catalyst: B₂ O₃ --Re₂ O₇ /Al₂ O₃--SiO₂ +Sn(n--C₄ H₉)₄

The experiment from Example 6 is repeated; however, instead of 4-octeneand 5-decane, 1-octene is now added and the molar ratio of theindividual components is set to Re₂ O₇ :SnBu₄ :1-octene=1:8:12,000.

After 3 hours at room temperature, a 42% conversion of 1-octene toethylene and 7-tetradecene with a selectivity of 86% is determined bymeans of gas chromatography.

Having described the present invention, it will be apparent to oneskilled in the art that many changes and modifications may be made tothe above-described embodiments without departing from the spirit andscope of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A catalyst for the metathesis of olefins andfunctionalized olefins, which consists essentially of B₂ O₃ --Re₂ O₇ onan Al₂ O₃ --SiO₂ substrate, wherein the B₂ O₃ --Re₂ O₇ content is from 2to 30% by weight, based on the Al₂ O₃ --SiO₂ content, and which catalystfurther contains an organo-tin compound having the formula SnR₄, whereinR is an alkyl group of from 1 to 8 carbon atoms.
 2. The catalyst ofclaim 1, wherein the molar ratio of Re₂ O₇ :SnR₄ ranges from 5:1 to 1:5.3. The catalyst of claim 2, wherein the molar ratio of Re₂ O₇ :SnR₄ranges from 2:1 to 1:2.
 4. The catalyst of claim 1, which has a B₂ O₃content of from 1 to 20% by weight.
 5. The catalyst of claim 4, whichhas a B₂ O₃ content of from 2 to 10% by weight.
 6. The catalyst of claim1, which has a Re₂ O₇ content of from 1 to 20% by weight.
 7. Thecatalyst of claim 6, which has a Re₂ O₇ content of from 2 to 15% byweight.
 8. The catalyst of claim 1, wherein R is selected from the groupconsisting of methyl, ethyl, isopropyl and n-butyl.